Knife sharpener
FIG. 1 is an enlarged perspective view of a knife sharpener, showing my new design; 
     FIG. 2 is a top plan view thereof; 
     FIG. 3 is a left side view, the right side being a mirror image thereof; 
     FIG. 4 is a front view, the rear view being a mirror image thereof; and 
     FIG. 5 is a bottom plan view thereof.